1
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Guo J, Šindelka M, Moiseyev N. Oscillating direct electric current formed by a resonant tunneling diode inside a cavity with periodically oscillating mirrors. J Chem Phys 2024; 161:044308. [PMID: 39051832 DOI: 10.1063/5.0205463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 07/09/2024] [Indexed: 07/27/2024] Open
Abstract
A novel phenomenon is described that enables the control of the flux of free electrons through a resonance tunneling diode (RTD) via coupling the RTD to a quantized electromagnetic mode in a dark cavity. As the control parameter, one uses here the distance between the two cavity mirrors (which are set to oscillate in time). The effect is illustrated by carrying out standard scattering calculations of the electron flux. However, the only efficient way to rationalize the phenomenon and to be able to select the proper distance between the two cavity mirrors is to employ non-Hermitian quantum mechanics and the language of discrete resonance poles of the scattering matrix. The demonstrated ability to control the flux of free electrons by using a dark cavity might open a new field of research and development of controllable RTD devices.
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Affiliation(s)
- Jiene Guo
- Department of Physics, Guangdong Technion - Israel Institute of Technology, 241 Daxue Road, Shantou, Guangdong 515063, China, and Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Milan Šindelka
- Institute of Plasma Physics of the Czech Academy of Sciences, Za Slovankou 1782/3, 18200 Prague 8, Czech Republic, and Helen Diller Quantum Center, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry and Faculty of Physics and Solid State Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
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2
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Elsaka B, Yang X, Kästner P, Dingel K, Sick B, Lehmann P, Buhmann SY, Hillmer H. Casimir Effect in MEMS: Materials, Geometries, and Metrologies-A Review. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3393. [PMID: 39063687 PMCID: PMC11278474 DOI: 10.3390/ma17143393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 06/29/2024] [Accepted: 07/02/2024] [Indexed: 07/28/2024]
Abstract
Casimir force densities, i.e., force per area, become very large if two solid material surfaces come closer together to each other than 10 nm. In most cases, the forces are attractive. In some cases, they can be repulsive depending on the solid materials and the fluid medium in between. This review provides an overview of experimental and theoretical studies that have been performed and focuses on four main aspects: (i) the combinations of different materials, (ii) the considered geometries, (iii) the applied experimental measurement methodologies and (iv) a novel self-assembly methodology based on Casimir forces. Briefly reviewed is also the influence of additional parameters such as temperature, conductivity, and surface roughness. The Casimir effect opens many application possibilities in microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS), where an overview is also provided. The knowledge generation in this fascinating field requires interdisciplinary approaches to generate synergetic effects between technological fabrication metrology, theoretical simulations, the establishment of adequate models, artificial intelligence, and machine learning. Finally, multiple applications are addressed as a research roadmap.
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Affiliation(s)
- Basma Elsaka
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Xiaohui Yang
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Philipp Kästner
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
| | - Kristina Dingel
- Institute for Systems Analytics and Control (ISAC), Intelligent Embedded Systems Department, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany; (K.D.); (B.S.)
- Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab between Helmholtz-Zentrum für Materialien und Energie, Berlin (HZB) and the University of Kassel, 34121 Kassel, Germany
| | - Bernhard Sick
- Institute for Systems Analytics and Control (ISAC), Intelligent Embedded Systems Department, University of Kassel, Wilhelmshöher Allee 71-73, 34121 Kassel, Germany; (K.D.); (B.S.)
- Artificial Intelligence Methods for Experiment Design (AIM-ED), Joint Lab between Helmholtz-Zentrum für Materialien und Energie, Berlin (HZB) and the University of Kassel, 34121 Kassel, Germany
| | - Peter Lehmann
- Measurement Technology Group, Faculty of Electrical Engineering and Computer Science, University of Kassel, Wilhelmshöher Allee 71, 34121 Kassel, Germany;
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Stefan Yoshi Buhmann
- Institut für Physik, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany;
| | - Hartmut Hillmer
- Institute of Nanostructure Technologies and Analytics (INA), Technological Electronics Department, University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.E.); (X.Y.); (P.K.)
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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3
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Grimm RT, Eaves JD. Direct Numerical Solutions to Stochastic Differential Equations with Multiplicative Noise. PHYSICAL REVIEW LETTERS 2024; 132:267101. [PMID: 38996310 DOI: 10.1103/physrevlett.132.267101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/25/2024] [Indexed: 07/14/2024]
Abstract
Inspired by path integral solutions to the quantum relaxation problem, we develop a numerical method to solve classical stochastic differential equations with multiplicative noise that avoids averaging over trajectories. To test the method, we simulate the dynamics of a classical oscillator multiplicatively coupled to non-Markovian noise. When accelerated using tensor factorization techniques, it accurately estimates the transition into the bifurcation regime of the oscillator and outperforms trajectory-averaging simulations with a computational cost that is orders of magnitude lower.
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Affiliation(s)
- Ryan T Grimm
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Joel D Eaves
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
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4
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Vázquez-Lozano JE, Liberal I. Review on the Scientific and Technological Breakthroughs in Thermal Emission Engineering. ACS APPLIED OPTICAL MATERIALS 2024; 2:898-927. [PMID: 38962569 PMCID: PMC11217951 DOI: 10.1021/acsaom.4c00030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 07/05/2024]
Abstract
The emission of thermal radiation is a physical process of fundamental and technological interest. From different approaches, thermal radiation can be regarded as one of the basic mechanisms of heat transfer, as a fundamental quantum phenomenon of photon production, or as the propagation of electromagnetic waves. However, unlike light emanating from conventional photonic sources, such as lasers or antennas, thermal radiation is characterized for being broadband, omnidirectional, and unpolarized. Due to these features, ultimately tied to its inherently incoherent nature, taming thermal radiation constitutes a challenging issue. Latest advances in the field of nanophotonics have led to a whole set of artificial platforms, ranging from spatially structured materials and, much more recently, to time-modulated media, offering promising avenues for enhancing the control and manipulation of electromagnetic waves, from far- to near-field regimes. Given the ongoing parallelism between the fields of nanophotonics and thermal emission, these recent developments have been harnessed to deal with radiative thermal processes, thereby forming the current basis of thermal emission engineering. In this review, we survey some of the main breakthroughs carried out in this burgeoning research field, from fundamental aspects to theoretical limits, the emergence of effects and phenomena, practical applications, challenges, and future prospects.
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Affiliation(s)
- J. Enrique Vázquez-Lozano
- Department of Electrical,
Electronic and Communications Engineering, Institute of Smart Cities
(ISC), Universidad Pública de Navarra
(UPNA), 31006 Pamplona, Spain
| | - Iñigo Liberal
- Department of Electrical,
Electronic and Communications Engineering, Institute of Smart Cities
(ISC), Universidad Pública de Navarra
(UPNA), 31006 Pamplona, Spain
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5
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Dantchev D. On Casimir and Helmholtz Fluctuation-Induced Forces in Micro- and Nano-Systems: Survey of Some Basic Results. ENTROPY (BASEL, SWITZERLAND) 2024; 26:499. [PMID: 38920508 PMCID: PMC11202628 DOI: 10.3390/e26060499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 06/27/2024]
Abstract
Fluctuations are omnipresent; they exist in any matter, due either to its quantum nature or to its nonzero temperature. In the current review, we briefly cover the quantum electrodynamic Casimir (QED) force as well as the critical Casimir (CC) and Helmholtz (HF) forces. In the QED case, the medium is usually a vacuum and the massless excitations are photons, while in the CC and HF cases the medium is usually a critical or correlated fluid and the fluctuations of the order parameter are the cause of the force between the macroscopic or mesoscopic bodies immersed in it. We discuss the importance of the presented results for nanotechnology, especially for devising and assembling micro- or nano-scale systems. Several important problems for nanotechnology following from the currently available experimental findings are spelled out, and possible strategies for overcoming them are sketched. Regarding the example of HF, we explicitly demonstrate that when a given integral quantity characterizing the fluid is conserved, it has an essential influence on the behavior of the corresponding fluctuation-induced force.
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Affiliation(s)
- Daniel Dantchev
- Institute of Mechanics, Bulgarian Academy of Sciences, Academic Georgy Bonchev St., Building 4, 1113 Sofia, Bulgaria;
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
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6
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Todorov Y, Dhillon S, Mangeney J. THz quantum gap: exploring potential approaches for generating and detecting non-classical states of THz light. NANOPHOTONICS 2024; 13:1681-1691. [PMID: 38681681 PMCID: PMC11052537 DOI: 10.1515/nanoph-2023-0757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/30/2023] [Indexed: 05/01/2024]
Abstract
Over the past few decades, THz technology has made considerable progress, evidenced by the performance of current THz sources and detectors, as well as the emergence of several THz applications. However, in the realm of quantum technologies, the THz spectral domain is still in its infancy, unlike neighboring spectral domains that have flourished in recent years. Notably, in the microwave domain, superconducting qubits currently serve as the core of quantum computers, while quantum cryptography protocols have been successfully demonstrated in the visible and telecommunications domains through satellite links. The THz domain has lagged behind in these impressive advancements. Today, the current gap in the THz domain clearly concerns quantum technologies. Nonetheless, the emergence of quantum technologies operating at THz frequencies will potentially have a significant impact. Indeed, THz radiation holds significant promise for wireless communications with ultimate security owing to its low sensitivity to atmospheric disturbances. Moreover, it has the potential to raise the operating temperature of solid-state qubits, effectively addressing existing scalability issues. In addition, THz radiation can manipulate the quantum states of molecules, which are recognized as new platforms for quantum computation and simulation with long range interactions. Finally, its ability to penetrate generally opaque materials or its resistance to Rayleigh scattering are very appealing features for quantum sensing. In this perspective, we will discuss potential approaches that offer exciting prospects for generating and detecting non-classical states of THz light, thereby opening doors to significant breakthroughs in THz quantum technologies.
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Affiliation(s)
- Yanko Todorov
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Juliette Mangeney
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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7
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Antezza M, Emelianova N, Khusnutdinov N. The normal Casimir-Lifshitz force for laterally moving graphene. NANOTECHNOLOGY 2024; 35:235001. [PMID: 38422611 DOI: 10.1088/1361-6528/ad2f1c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
We consider the system of two parallel sheets of graphene which are moving with relative parallel velocityv⃗and calculate the Casimir energy by using the scattering approach. We analyze in detail the normal (perpendicular to the planes) Casimir force for two systems-graphene/graphene and ideal metal/graphene. In the non-relativistic casev≪vF, the relative correction to the Casimir energy(Ev-E0)/E0is proportional to the (v/c)2(the maximum value is 0.0033 for the gapeless case andv=vF) for the first system, and it is zero up to the Fermi velocityv=vFfor system ideal metal/graphene.
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Affiliation(s)
- Mauro Antezza
- Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-University of Montpellier, F-34095 Montpellier, France
- Institut Universitaire de France, 1 rue Descartes, Paris Cedex 05 F-75231, France
| | - N Emelianova
- CMCC, Universidade Federal do ABC, Avenida dos Estados 5001, CEP 09210-580, SP, Brazil
| | - N Khusnutdinov
- CMCC, Universidade Federal do ABC, Avenida dos Estados 5001, CEP 09210-580, SP, Brazil
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8
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Del Grosso NF, Lombardo FC, Mazzitelli FD, Villar PI. Adiabatic Shortcuts Completion in Quantum Field Theory: Annihilation of Created Particles. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1249. [PMID: 37761548 PMCID: PMC10529776 DOI: 10.3390/e25091249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/16/2023] [Accepted: 08/19/2023] [Indexed: 09/29/2023]
Abstract
Shortcuts to adiabaticity (STA) are relevant in the context of quantum systems, particularly regarding their control when they are subjected to time-dependent external conditions. In this paper, we investigate the completion of a nonadiabatic evolution into a shortcut to adiabaticity for a quantum field confined within a one-dimensional cavity containing two movable mirrors. Expanding upon our prior research, we characterize the field's state using two Moore functions that enables us to apply reverse engineering techniques in constructing the STA. Regardless of the initial evolution, we achieve a smooth extension of the Moore functions that implements the STA. This extension facilitates the computation of the mirrors' trajectories based on the aforementioned functions. Additionally, we draw attention to the existence of a comparable problem within nonrelativistic quantum mechanics.
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Affiliation(s)
- Nicolás F. Del Grosso
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina;
- Instituto de Física de Buenos Aires (IFIBA), CONICET—Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Fernando C. Lombardo
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina;
- Instituto de Física de Buenos Aires (IFIBA), CONICET—Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Francisco D. Mazzitelli
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, Bariloche 8400, Argentina;
| | - Paula I. Villar
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina;
- Instituto de Física de Buenos Aires (IFIBA), CONICET—Universidad de Buenos Aires, Buenos Aires 1428, Argentina
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9
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Vázquez-Lozano JE, Liberal I. Incandescent temporal metamaterials. Nat Commun 2023; 14:4606. [PMID: 37528085 PMCID: PMC10394077 DOI: 10.1038/s41467-023-40281-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 07/18/2023] [Indexed: 08/03/2023] Open
Abstract
Regarded as a promising alternative to spatially shaping matter, time-varying media can be seized to control and manipulate wave phenomena, including thermal radiation. Here, based upon the framework of macroscopic quantum electrodynamics, we elaborate a comprehensive quantum theoretical formulation that lies the basis for investigating thermal emission effects in time-modulated media. Our theory unveils unique physical features brought about by time-varying media: nontrivial correlations between fluctuating electromagnetic currents at different frequencies and positions, thermal radiation overcoming the black-body spectrum, and quantum vacuum amplification effects at finite temperature. We illustrate how these features lead to striking phenomena and innovative thermal emitters, specifically, showing that the time-modulation releases strong field fluctuations confined within epsilon-near-zero (ENZ) bodies, and that, in turn, it enables a narrowband (partially coherent) emission spanning the whole range of wavevectors, from near to far-field regimes.
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Affiliation(s)
- J Enrique Vázquez-Lozano
- Department of Electrical, Electronic and Communications Engineering, Institute of Smart Cities (ISC), Universidad Pública de Navarra (UPNA), 31006, Pamplona, Spain.
| | - Iñigo Liberal
- Department of Electrical, Electronic and Communications Engineering, Institute of Smart Cities (ISC), Universidad Pública de Navarra (UPNA), 31006, Pamplona, Spain.
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10
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de Paula MVS, Sinesio WWT, Dodonov AV. Ancilla-Assisted Generation of Photons from Vacuum via Time-Modulation of Extracavity Qubit. ENTROPY (BASEL, SWITZERLAND) 2023; 25:901. [PMID: 37372245 DOI: 10.3390/e25060901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/14/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023]
Abstract
We propose a scheme for the generation of photons from a vacuum via time-modulation of a quantum system indirectly coupled to the cavity field through some ancilla quantum subsystem. We consider the simplest case when the modulation is applied to an artificial two-level atom (we call 't-qubit', that can be located even outside the cavity), while the ancilla is a stationary qubit coupled via the dipole interaction both to the cavity and t-qubit. We find that tripartite entangled states with a small number of photons can be generated from the system ground state under resonant modulations, even when the t-qubit is far detuned from both the ancilla and the cavity, provided its bare and modulation frequencies are properly adjusted. We attest our approximate analytic results by numeric simulations and show that photon generation from vacuum persists in the presence of common dissipation mechanisms.
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Affiliation(s)
- Marcos V S de Paula
- Institute of Physics, University of Brasilia, Caixa Postal 04455, Brasilia 70910-900, DF, Brazil
| | - William W T Sinesio
- Institute of Physics, University of Brasilia, Caixa Postal 04455, Brasilia 70910-900, DF, Brazil
| | - Alexandre V Dodonov
- Institute of Physics, University of Brasilia, Caixa Postal 04455, Brasilia 70910-900, DF, Brazil
- International Center of Physics, Institute of Physics, University of Brasilia, Brasilia 70910-900, DF, Brazil
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11
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Mantiñan M, Mazzitelli FD, Trombetta LG. Stochastic Particle Creation: From the Dynamical Casimir Effect to Cosmology. ENTROPY (BASEL, SWITZERLAND) 2023; 25:151. [PMID: 36673292 PMCID: PMC9857574 DOI: 10.3390/e25010151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/07/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
We study a stochastic version of the dynamical Casimir effect, computing the particle creation inside a cavity produced by a random motion of one of its walls. We first present a calculation perturbative in the amplitude of the motion. We compare the stochastic particle creation with the deterministic counterpart. Then, we go beyond the perturbative evaluation using a stochastic version of the multiple scale analysis, that takes into account stochastic parametric resonance. We stress the relevance of the coupling between the different modes induced by the stochastic motion. In the single-mode approximation, the equations are formally analogous to those that describe the stochastic particle creation in a cosmological context, that we rederive using multiple scale analysis.
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Affiliation(s)
- Matías Mantiñan
- Department of Physics, University of Chicago, Chicago, IL 60637, USA
| | - Francisco D. Mazzitelli
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, Bariloche R8402AGP, Argentina
| | - Leonardo G. Trombetta
- CEICO, Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 18221 Prague, Czech Republic
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12
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Del Grosso NF, Lombardo FC, Mazzitelli FD, Villar PI. Fast Adiabatic Control of an Optomechanical Cavity. ENTROPY (BASEL, SWITZERLAND) 2022; 25:18. [PMID: 36673159 PMCID: PMC9857496 DOI: 10.3390/e25010018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/07/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
The development of quantum technologies present important challenges such as the need for fast and precise protocols for implementing quantum operations. Shortcuts to adiabaticity (STAs) are a powerful tool for achieving these goals, as they enable us to perform an exactly adiabatic evolution in finite time. In this paper, we present a shortcut to adiabaticity for the control of an optomechanical cavity with two moving mirrors. Given reference trajectories for the mirrors, we find analytical expressions that give us effective trajectories which implement an STA for the quantum field inside the cavity. We then solve these equations numerically for different reference protocols, such as expansions, contractions and rigid motions, thus confirming the successful implementation of the STA and finding some general features of these effective trajectories.
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Affiliation(s)
- Nicolás F. Del Grosso
- Departamento de Física Juan José Giambiagi, FCEyN UBA and IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Pabellón I, Buenos Aires 1428, Argentina
| | - Fernando C. Lombardo
- Departamento de Física Juan José Giambiagi, FCEyN UBA and IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Pabellón I, Buenos Aires 1428, Argentina
| | - Francisco D. Mazzitelli
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, Bariloche 8400, Argentina
| | - Paula I. Villar
- Departamento de Física Juan José Giambiagi, FCEyN UBA and IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Pabellón I, Buenos Aires 1428, Argentina
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13
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Tian Z, Wu L, Zhang L, Jing J, Du J. Probing Lorentz-invariance-violation-induced nonthermal Unruh effect in quasi-two-dimensional dipolar condensates. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.l061701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Fosco CD, Lombardo FC, Mazzitelli FD. Motion induced excitation and electromagnetic radiation from an atom facing a thin mirror. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.065005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Dong H, Reiche D, Hsiang JT, Hu BL. Quantum Thermodynamic Uncertainties in Nonequilibrium Systems from Robertson-Schrödinger Relations. ENTROPY 2022; 24:e24070870. [PMID: 35885093 PMCID: PMC9324490 DOI: 10.3390/e24070870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/15/2022] [Accepted: 06/19/2022] [Indexed: 02/05/2023]
Abstract
Thermodynamic uncertainty principles make up one of the few rare anchors in the largely uncharted waters of nonequilibrium systems, the fluctuation theorems being the more familiar. In this work we aim to trace the uncertainties of thermodynamic quantities in nonequilibrium systems to their quantum origins, namely, to the quantum uncertainty principles. Our results enable us to make this categorical statement: For Gaussian systems, thermodynamic functions are functionals of the Robertson-Schrödinger uncertainty function, which is always non-negative for quantum systems, but not necessarily so for classical systems. Here, quantum refers to noncommutativity of the canonical operator pairs. From the nonequilibrium free energy, we succeeded in deriving several inequalities between certain thermodynamic quantities. They assume the same forms as those in conventional thermodynamics, but these are nonequilibrium in nature and they hold for all times and at strong coupling. In addition we show that a fluctuation-dissipation inequality exists at all times in the nonequilibrium dynamics of the system. For nonequilibrium systems which relax to an equilibrium state at late times, this fluctuation-dissipation inequality leads to the Robertson-Schrödinger uncertainty principle with the help of the Cauchy-Schwarz inequality. This work provides the microscopic quantum basis to certain important thermodynamic properties of macroscopic nonequilibrium systems.
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Affiliation(s)
- Hang Dong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China;
| | - Daniel Reiche
- Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany;
| | - Jen-Tsung Hsiang
- Center for High Energy and High Field Physics, National Central University, Taoyuan 320317, Taiwan
- Correspondence:
| | - Bei-Lok Hu
- Maryland Center for Fundamental Physics and Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA;
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16
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Analogue cosmological particle creation in an ultracold quantum fluid of light. Nat Commun 2022; 13:2890. [PMID: 35614054 PMCID: PMC9133100 DOI: 10.1038/s41467-022-30603-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/10/2022] [Indexed: 12/01/2022] Open
Abstract
The rapid expansion of the early universe resulted in the spontaneous production of cosmological particles from vacuum fluctuations, some of which are observable today in the cosmic microwave background anisotropy. The analogue of cosmological particle creation in a quantum fluid was proposed, but the quantum, spontaneous effect due to vacuum fluctuations has not yet been observed. Here we report the spontaneous creation of analogue cosmological particles in the laboratory, using a quenched 3-dimensional quantum fluid of light. We observe acoustic peaks in the density power spectrum, in close quantitative agreement with the quantum-field theoretical prediction. We find that the long-wavelength particles provide a window to early times. This work introduces the quantum fluid of light, as cold as an atomic Bose-Einstein condensate. Under certain conditions light can act as a fluid like a Bose-Einstein condensate. Here the authors discuss an analogy of cosmological particle creation using such a quantum fluid of light.
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Abstract
An important yet perplexing result from work in the 1990s and 2000s is the near-unity value of the ratio of fluctuations in the vacuum energy density of quantum fields to the mean in a collection of generic spacetimes. This was carried out by way of calculating the noise kernels which are the correlators of the stress-energy tensor of quantum fields. In this paper, we revisit this issue via a quantum thermodynamics approach, by calculating two quintessential thermodynamic quantities: the heat capacity and the quantum compressibility of some model geometries filled with a quantum field at high and low temperatures. This is because heat capacity at constant volume gives a measure of the fluctuations of the energy density to the mean. When this ratio approaches or exceeds unity, the validity of the canonical distribution is called into question. Likewise, a system’s compressibility at constant pressure is a criterion for the validity of grand canonical ensemble. We derive the free energy density and, from it, obtain the expressions for these two thermodynamic quantities for thermal and quantum fields in 2d Casimir space, 2d Einstein cylinder and 4d (S1×S3 ) Einstein universe. To examine the dependence on the dimensionality of space, for completeness, we have also derived these thermodynamic quantities for the Einstein universes with even-spatial dimensions: S1×S2 and S1×S4. With this array of spacetimes we can investigate the thermodynamic stability of quantum matter fields in them and make some qualitative observations on the compatibility condition for the co-existence between quantum fields and spacetimes, a fundamental issue in the quantum and gravitation conundrum.
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Hsiang JT, Hu BL. Intrinsic Entropy of Squeezed Quantum Fields and Nonequilibrium Quantum Dynamics of Cosmological Perturbations. ENTROPY 2021; 23:e23111544. [PMID: 34828242 PMCID: PMC8621705 DOI: 10.3390/e23111544] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/02/2021] [Accepted: 11/11/2021] [Indexed: 11/30/2022]
Abstract
Density contrasts in the universe are governed by scalar cosmological perturbations which, when expressed in terms of gauge-invariant variables, contain a classical component from scalar metric perturbations and a quantum component from inflaton field fluctuations. It has long been known that the effect of cosmological expansion on a quantum field amounts to squeezing. Thus, the entropy of cosmological perturbations can be studied by treating them in the framework of squeezed quantum systems. Entropy of a free quantum field is a seemingly simple yet subtle issue. In this paper, different from previous treatments, we tackle this issue with a fully developed nonequilibrium quantum field theory formalism for such systems. We compute the covariance matrix elements of the parametric quantum field and solve for the evolution of the density matrix elements and the Wigner functions, and, from them, derive the von Neumann entropy. We then show explicitly why the entropy for the squeezed yet closed system is zero, but is proportional to the particle number produced upon coarse-graining out the correlation between the particle pairs. We also construct the bridge between our quantum field-theoretic results and those using the probability distribution of classical stochastic fields by earlier authors, preserving some important quantum properties, such as entanglement and coherence, of the quantum field.
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Affiliation(s)
- Jen-Tsung Hsiang
- Center for High Energy and High Field Physics, National Central University, Taoyuan 32001, Taiwan
- Correspondence:
| | - Bei-Lok Hu
- Maryland Center for Fundamental Physics and Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA;
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Barbado LC, Báez-Camargo AL, Fuentes I. Evolution of confined quantum scalar fields in curved spacetime. Part II: Spacetimes with moving boundaries in any synchronous gauge. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2021; 81:953. [PMID: 34744505 PMCID: PMC8553737 DOI: 10.1140/epjc/s10052-021-09737-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/13/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
We develop a method for computing the Bogoliubov transformation experienced by a confined quantum scalar field in a globally hyperbolic spacetime, due to the changes in the geometry and/or the confining boundaries. The method constructs a basis of solutions to the Klein-Gordon equation associated to each compact Cauchy hypersurface of constant time. It then provides a differential equation for the linear transformation between bases at different times. The transformation can be interpreted physically as a Bogoliubov transformation when it connects two regions in which a time symmetry allows for a Fock quantisation. This second article on the method is dedicated to spacetimes with timelike boundaries that do not remain static in any synchronous gauge. The method proves especially useful in the regime of small perturbations, where it allows one to easily make quantitative predictions on the amplitude of the resonances of the field. Therefore, it provides a crucial tool in the growing research area of confined quantum fields in table-top experiments. We prove this utility by addressing two problems in the perturbative regime: Dynamical Casimir Effect and gravitational wave resonance. We reproduce many previous results on these phenomena and find novel results in an unified way. Possible extensions of the method are indicated. We expect that our method will become standard in quantum field theory for confined fields.
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Affiliation(s)
- Luis C. Barbado
- Quantenoptik, Quantennanophysik und Quanteninformation, Fakultät für Physik, Universität Wien, Boltzmanngasse 5, 1090 Vienna, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria
| | - Ana L. Báez-Camargo
- Quantenoptik, Quantennanophysik und Quanteninformation, Fakultät für Physik, Universität Wien, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Ivette Fuentes
- Quantenoptik, Quantennanophysik und Quanteninformation, Fakultät für Physik, Universität Wien, Boltzmanngasse 5, 1090 Vienna, Austria
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
- School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ UK
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Falling from Rest: Particle Creation in a Dropped Cavity. Symmetry (Basel) 2021. [DOI: 10.3390/sym13071139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We discuss the process of particle creation in the case of a scalar quantum field confined to a small cavity, initially at rest, which is suddenly dropped in a static gravitational field. We show that, due to the transition from a Schwarzschild to a Minkowski background, as perceived by a comoving observer, field particles are excited out of the quantum vacuum. The density of the created quanta depends on the proper gravitational acceleration as well as on a parameter α≃1/Δt, with Δt representing the typical time duration of the transition. For the specific acceleration profile considered, the energy spectrum of the created quanta roughly resembles a two-dimensional Planckian distribution, whose equivalent temperature mimics the Hawking-Unruh temperature, with the detector acceleration (or the black hole surface gravity) replaced by the parameter cα. We briefly comment on possible issues related to local Lorentz symmetry.
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Abstract
We study the motion-induced radiation due to the non-relativistic motion of an atom, coupled to the vacuum electromagnetic field by an electric dipole term, in the presence of a static graphene plate. After computing the probability of emission for an accelerated atom in empty space, we evaluate the corrections due to the presence of the plate. We show that the effect of the plate is to increase the probability of emission when the atom is near the plate and oscillates along a direction perpendicular to it. On the contrary, for parallel oscillations, there is a suppression. We also evaluate the quantum friction on an atom moving at constant velocity parallel to the plate. We show that there is a threshold for quantum friction: friction occurs only when the velocity of the atom is larger than the Fermi velocity of the electrons in graphene.
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Quantum Power Distribution of Relativistic Acceleration Radiation: Classical Electrodynamic Analogies with Perfectly Reflecting Moving Mirrors. Symmetry (Basel) 2021. [DOI: 10.3390/sym13040653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We find the quantum power emitted and distribution in 3 + 1-dimensions of relativistic acceleration radiation using a single perfectly reflecting mirror via Lorentz invariance, demonstrating close analogies to point charge radiation in classical electrodynamics.
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Route to Extend the Lifetime of a Discrete Time Crystal in a Finite Spin Chain without Disorder. ATOMS 2021. [DOI: 10.3390/atoms9020025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Periodically driven (Floquet) systems are described by time-dependent Hamiltonians that possess discrete time translation symmetry. The spontaneous breaking of this symmetry leads to the emergence of a novel non-equilibrium phase of matter—the Discrete Time Crystal (DTC). In this paper, we propose a scheme to extend the lifetime of a DTC in a paradigmatic model—a translation-invariant Ising spin chain with nearest-neighbor interaction J, subjected to a periodic kick by a transverse magnetic field with frequency 2πT. This system exhibits the hallmark signature of a DTC—persistent sub-harmonic oscillations with frequency πT—for a wide parameter regime. Employing both analytical arguments as well as exact diagonalization calculations, we demonstrate that the lifetime of the DTC is maximized, when the interaction strength is tuned to an optimal value, JT=π. Our proposal essentially relies on an interaction-induced quantum interference mechanism that suppresses the creation of excitations, and thereby enhances the DTC lifetime. Intriguingly, we find that the period doubling oscillations can last eternally in even size systems. This anomalously long lifetime can be attributed to a time reflection symmetry that emerges at JT=π. Our work provides a promising avenue for realizing a robust DTC in various quantum emulator platforms.
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Abstract
This is a very basic and pedagogical review of the concepts of zeta function and of the associated zeta regularization method, starting from the notions of harmonic series and of divergent sums in general. By way of very simple examples, it is shown how these powerful methods are used for the regularization of physical quantities, such as quantum vacuum fluctuations in various contexts. In special, in Casimir effect setups, with a note on the dynamical Casimir effect, and mainly concerning its application in quantum theories in curved spaces, subsequently used in gravity theories and cosmology. The second part of this work starts with an essential introduction to large scale cosmology, in search of the observational foundations of the Friedmann-Lemaître-Robertson-Walker (FLRW) model, and the cosmological constant issue, with the very hard problems associated with it. In short, a concise summary of all these interrelated subjects and applications, involving zeta functions and the cosmos, and an updated list of the pioneering and more influential works (according to Google Scholar citation counts) published on all these matters to date, are provided.
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Perspective on Some Recent and Future Developments in Casimir Interactions. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app11010293] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Here, we present a critical review of recent developments in Casimir physics motivated by discoveries of novel materials. Specifically, topologically nontrivial properties of the graphene family, Chern and topological insulators, and Weyl semimetals have diverse manifestations in the distance dependence, presence of fundamental constants, magnitude, and sign of the Casimir interaction. Limited studies of the role of nonlinear optical properties in the interaction are also reviewed. We show that, since many new materials have greatly enhanced the nonlinear optical response, new efficient pathways for investigation of the characteristic regimes of the Casimir force need to be explored, which are expected to lead to new discoveries. Recent progress in the dynamical Casimir effect is also reviewed and we argue that nonlinear media can open up new directions in this field as well.
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PT
-Symmetric Qubit-System States in the Probability Representation of Quantum Mechanics. Symmetry (Basel) 2020. [DOI: 10.3390/sym12101702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
PT-symmetric qubit-system states are considered in the probability representation of quantum mechanics. The new energy eigenvalue equation for probability distributions identified with qubit and qutrit states is presented in an explicit form. A possibility to test PT-symmetry and its violation by measuring the probabilities of spin projections for qubits in three perpendicular directions is discussed.
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Good M, Juárez-Aubry BA, Moustos D, Temirkhan M. Unruh-like effects: effective temperatures along stationary worldlines. JOURNAL OF HIGH ENERGY PHYSICS : JHEP 2020; 2020:59. [PMID: 32536781 PMCID: PMC7282697 DOI: 10.1007/jhep06(2020)059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/18/2020] [Indexed: 06/11/2023]
Abstract
We study the detailed balance temperatures recorded along all classes of stationary, uniformly accelerated worldlines in four-dimensional Minkowski spacetime, namely along (i) linear uniform acceleration, (ii) cusped, (iii) circular, (iv) catenary, and (v) helix worldlines, among which the Unruh temperature is the particular case for linear uniform acceleration. As a measuring device, we employ an Unruh-DeWitt detector, modeled as a qubit that interacts for a long time with a massless Klein-Gordon field in the vacuum state. The temperatures in each case (i) - (v) are functions of up to three invariant quantities: curvature or proper acceleration, κ, torsion, b, and hypertorsion, ν, and except for the case (i), they depend on the transition frequency difference of the detector, ω. We investigate numerically the behavior of the frequency-dependent temperatures for different values of κ, b, and ν along the stationary worldlines (ii) - (v) and evaluate analytically the regimes where the temperatures recorded along the different worldlines coincide with each other in terms of relevant asymptotic limits for κ, b, or ν, and discuss their physical meaning. We demonstrate that the temperatures in cases (ii) - (v) dip under the Unruh temperature at low frequencies and go above the Unruh temperature for large |ω|. It is our hope that this study will be relevant to the design of experiments seeking to verify the Unruh effect or generalizations thereof.
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Affiliation(s)
- Michael Good
- Department of Physics, Nazarbayev University, Nur-Sultan, Kazakhstan 010000
| | - Benito A. Juárez-Aubry
- Departmento de Física Matemática, Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, 20126 Mexico City, Mexico
| | - Dimitris Moustos
- Department of Physics, University of Patras, 26504 Patras, Greece
| | - Maksat Temirkhan
- Department of Physics, Nazarbayev University, Nur-Sultan, Kazakhstan 010000
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Differential Parametric Formalism for the Evolution of Gaussian States: Nonunitary Evolution and Invariant States. ENTROPY 2020; 22:e22050586. [PMID: 33286358 PMCID: PMC7517105 DOI: 10.3390/e22050586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 11/29/2022]
Abstract
In the differential approach elaborated, we study the evolution of the parameters of Gaussian, mixed, continuous variable density matrices, whose dynamics are given by Hermitian Hamiltonians expressed as quadratic forms of the position and momentum operators or quadrature components. Specifically, we obtain in generic form the differential equations for the covariance matrix, the mean values, and the density matrix parameters of a multipartite Gaussian state, unitarily evolving according to a Hamiltonian H^. We also present the corresponding differential equations, which describe the nonunitary evolution of the subsystems. The resulting nonlinear equations are used to solve the dynamics of the system instead of the Schrödinger equation. The formalism elaborated allows us to define new specific invariant and quasi-invariant states, as well as states with invariant covariance matrices, i.e., states were only the mean values evolve according to the classical Hamilton equations. By using density matrices in the position and in the tomographic-probability representations, we study examples of these properties. As examples, we present novel invariant states for the two-mode frequency converter and quasi-invariant states for the bipartite parametric amplifier.
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